SQL to Select only full groups of data - sql

Question

Let's say I have three sample tables for groups of people as shown below.
Table users:
id
name
available
1
John
true
2
Nick
true
3
Sam
false
Table groups:
id
name
1
study
2
games
Table group_users:
group_id
user_id
role
1
1
teach
1
2
stdnt
1
3
stdnt
2
1
tank
2
2
heal
And I need to show to a user all groups that he participates in and also available right now, which means all users in that group have users.available = true.
I tried something like:
SELECT `groups`.*, `users`.* , `group_users`.*
FROM `groups`
LEFT JOIN `group_users` ON `groups`.`id` = `group_users`.`group_id`
LEFT JOIN `users` ON `users`.`id` = `group_users`.`user_id`
WHERE `users`.`available` = true AND `users`.`id` = 1
But it just shows groups and part of their users, that are available. And I need to have ONLY the groups that have all their users available.
If I were to find all available groups as User 1 - I should get only group 2 and it's users. How to do this the right way?
Tables DDL:
CREATE TABLE users (
id int PRIMARY KEY,
name varchar(256) NOT NULL,
available bool
);
CREATE TABLE teams (
id int PRIMARY KEY,
name varchar(256) NOT NULL
);
CREATE TABLE team_users (
team_id int NOT NULL,
user_id int NOT NULL,
role varchar(64)
);
INSERT INTO users VALUES
(1, 'John', true ),
(2, 'Nick', true ),
(3, 'Sam' , false);
INSERT INTO teams VALUES
(1, 'study'),
(2, 'games');
INSERT INTO team_users VALUES
(1, 1, 'teach'),
(1, 2, 'stdnt'),
(1, 3, 'stdnt'),
(2, 1, 'tank' ),
(2, 2, 'heal' );
mySQL select version() output:
10.8.3-MariaDB-1:10.8.3+maria~jammy

Answer 1

Check do you need in this:
WITH cte AS (
SELECT users.name username,
teams.id teamid,
teams.name teamname,
SUM(NOT users.available) OVER (PARTITION BY teams.id) non_availabe_present,
SUM(users.name = #user_name) OVER (PARTITION BY teams.id) needed_user_present
FROM team_users
JOIN users ON team_users.user_id = users.id
JOIN teams ON team_users.team_id = teams.id
)
SELECT username, teamid, teamname
FROM cte
WHERE needed_user_present
AND NOT non_availabe_present;
https://dbfiddle.uk/?rdbms=mysql_8.0&fiddle=605cf10d147fd904fb2d4a6cd5968302
PS. I use user name as a criteria, you may edit and use user's identifier, of course.

Answer 2

Join the tables and aggregate with the conditions in the HAVING clause:
SELECT t.id, t.name
FROM teams t
INNER JOIN team_users tu ON t.id = tu.team_id
INNER JOIN users u ON u.id = tu.user_id
GROUP BY t.id
HAVING MIN(u.available) AND SUM(u.id = 1);
The HAVING clause is a simplification of:
HAVING MIN(u.available) = true AND SUM(u.id = 1) > 0
See the demo.

Answer 3

first you need to find those group which users is available. then find the all the group details of those group which is not related to those group which user is available.
SELECT * FROM team_users a
JOIN teams b ON a.team_id=b.id
JOIN users c ON a.user_id=c.id
WHERE NOT EXISTS
(
SELECT 1 FROM team_users tu
JOIN users u ON tu.user_id=u.id AND u.available =1
WHERE tu.team_id=a.Team_id
)